1. Technical Field
This disclosure relates to a cleaner, and to an image forming apparatus using the cleaner.
2. Description of the Related Art
Cleaners to remove residual toner using an electrostatic force have been used for removing residual toner on an intermediate transfer belt of image forming apparatus using an intermediate transfer method.
Specific examples of such cleaners include a cleaner in which three cleaning brush rollers serving as cleaning members are arranged side by side in a rotation direction of an intermediate transfer belt. One of the three cleaning brush rollers, which is arranged on the extreme upstream side relative to the rotation direction of the intermediate transfer belt, is a pre-cleaning brush roller to roughly remove normally charged toner on the intermediate transfer belt. The second cleaning brush roller, which is arranged on a downstream side from the pre-cleaning brush roller relative to the rotation direction of the intermediate transfer belt, removes reversely charged toner on the intermediate transfer belt. The third cleaning brush roller, which is arranged on a downstream side from the second cleaning brush roller relative to the rotation direction of the intermediate transfer belt, removes normally charged toner on the intermediate transfer belt. The cleaner further includes first, second and third toner collecting rollers to collect toner adhered to the corresponding cleaning brush rollers, and first, second and third scraping blades to scrape off toner adhered to the surface of the corresponding toner collecting rollers.
When a targeted voltage is applied to the pre-cleaning brush roller of the cleaner so that the pre-cleaning brush roller can generate a desired electrostatic force, the current flowing through the contact portion of the pre-cleaning brush roller with the intermediate transfer belt is detected. A power controller of a power source of the cleaner outputs a control signal to a power output member of the power source so that the power output member outputs the targeted voltage to the pre-cleaning brush roller, thereby generating the desired electrostatic force for the pre-cleaning brush roller.
The voltage applied by the power output member to the first toner collecting roller is adjusted so as to be the targeted voltage at which the difference between the potential of the pre-cleaning brush roller and the potential of the first toner collecting roller becomes a predetermined value (e.g., 400V) and a desired electrostatic force is formed on the first toner collecting roller such that the first toner collecting roller can collect the toner adhered to the pre-cleaning brush roller. In this regard, the absolute value of the targeted voltage applied to the first toner collecting roller is greater than that of the targeted voltage applied to the pre-cleaning brush roller.
Similarly to the case of the pre-cleaning brush roller, other power output members respectively apply targeted voltages to the second and third cleaning brush rollers. In addition, similarly to the case of the first toner collecting roller, the power controller outputs control signals to the corresponding power output members so that the power output members can apply targeted voltages to the second and third toner collecting rollers. Thus, desired electrostatic forces are generated for the first to third cleaning brush rollers and the first to third toner collecting rollers.
In this cleaner, the pre-cleaning brush roller, which is arranged on the extreme upstream side relative to the rotation direction of the intermediate transfer belt, roughly removes normally charged toner particles, which account for most of the residual (non-transferred) toner particles, and therefore the amount of the residual toner particles remaining on the intermediate transfer belt and being fed to the second cleaning brush roller (i.e., reversely charged toner cleaning brush roller) and the third cleaning brush roller (i.e., normally charged toner cleaning brush roller) is small. Therefore, the second and third cleaning brush rollers can easily remove the residual toner particles remaining on the intermediate transfer belt, resulting in enhancement of the cleaning effect.